Briton Johanna Konta's Wimbledon preparations were damaged by a second-round loss to Jelena Ostapenko in the second round in Birmingham.
The seventh seed, who reached the French Open semi-finals, was beaten 6-3 6-4 by the Latvian world number 37.
Konta missed last week's Nottingham event and will now hope to gather more match time on grass at Eastbourne next week before Wimbledon starts on 1 July.
French Open champion Ashleigh Barty and Venus Williams advanced to round two.
Czech identical twins Karolina and Kristyna Pliskova meet in the second round later on Wednesday.
Konta had been the only Briton left in a strong field at the Edgbaston Priory Club after first-round defeats for Harriet Dart and Heather Watson.
And after a strong clay-court season, where she reached two WTA finals on the surface as well as the last four at Roland Garros, she had hoped to continue her good form on to the grass.
But the 2017 Wimbledon semi-finalist failed to make it past the second round in Birmingham for the seventh successive year.
Ostapenko, the 2017 French Open champion and also a semi-finalist at Wimbledon last year, won the first three games of the match to stamp her authority early on.
The devastating serve that the Briton had used to such great effect at the French Open let her down as she won 59% of her first-serve points.
She showed fighting spirit when she faced set point on her serve in the eighth game of the first set, saving it to force the Latvian to serve it out.
She also overturned an early break in the second set but then immediately lost her next service game to give Ostapenko sight of the finishing line.
Konta finally succumbed when she hit a fairly routine baseline shot long after an hour and 19 minutes.
"Of course I'm trying to play aggressively. She is a such a great server so I had no choice and I had to serve well. Johanna is such a fighter and you always have to play until the last point - I've tried to be very focused," said Ostapenko.
"I'm more hungry now as I've not had many wins this year."
The 22-year-old will now play either Russia's Margarita Gasparyan or Croatia's Petra Martic in the last eight.
French Open champion Barty got her grass-court season off to a winning start with victory over Donna Vekic.
The 23-year-old Australian recovered from an early break in the first set to beat the Croat 6-3 6-4.
She is joined in the second round by seven-time Grand Slam champion Williams, who beat Belarusian Aliaksandra Sasnovich 6-3 6-4.
Barty and Williams' matches were among several to be postponed when play was suspended because of rain on Tuesday.
After a wobbly start against Vekic, Barty won five games in a row from the seventh game in the first set to set up a meeting with American Jennifer Brady, who beat Lesia Tsurenko 6-3 6-3.
Vekic, runner-up at the Nottingham grass event on Sunday, staged a mini fightback when she broke Barty during the Australian's first opportunity to serve for the match, but Barty sealed victory in her next service game.
Barty said that playing as a Grand Slam champion had freed her up, rather than putting pressure on her shoulders.
"I can just go out and enjoy it, enjoy every single match. It is an opportunity to try and be better and really go out there and just have fun," she said.
"It was really nice to come out now and kind of get back into a normal routine of playing matches again."
Meanwhile, 39-year-old Williams - who accepted a wildcard to make her first appearance at the Edgbaston Priory Club - put in a solid performance against world number 36 Sasnovich with less than two weeks to go until the start of Wimbledon.
It is only the fourth time Williams has played in a grass-court event before Wimbledon. She appeared in the doubles here earlier in the week but her surprise partnership with Briton Harriet Dart ended in a first-round defeat.
The American will face China's Wang Qiang in the second round of the singles.